Spizaetus nanus, S. lanceolatus, S. philippensis, S. pinskeri, S. nipalensis, S. alboniger and S. bartelsi (Sibley and Monroe 1990, 1993) and S. cirrhatus and S. floris (Gjershaug et al. 2004) have been transferred into the genus Nisaetus following Haring et al. (2006). S. africanus and Hieraaetus fasciatus (Sibley and Monroe 1990, 1993) have both been transferred into Aquila, also following Haring et al. (2006); and H. kienerii (Sibley and Monroe 1990, 1993) has been transferred into the resurrected genus Lophotriorchis. The BirdLife Taxonomic Working Group is aware that phylogenetic analyses have been published which have proposed moving H. pennatus into Aquila but as not all published studies are concordant we prefer not to take a decision on this until cladogenesis of the "booted eagles" has been resolved.

Justification:
The population of this impressive raptor is very small. Moreover, given the destruction, disturbance and degradation that is currently being inflicted on its preferred habitat, it is likely to be declining and increasingly fragmented, a circumstance that qualifies it as Endangered.

Spizaetus bartelsi is endemic to the island of Java, Indonesia, where it is restricted to remaining patches of forest and is consequently scarce (BirdLife International 2001). An increase in survey effort and knowledge of the species's home-range size has led to consecutive upward revisions of the global population, now estimated at over 600 individuals (Prawiradilaga 2004), with one estimate of 270-600 pairs (Gjershaug et al. 2004). It is distributed widely throughout much of the island with a recent increase in the number of known localities, although it remains unrecorded from large areas of the north. Although there is no direct indication of a decline, with the species always considered rare, the on-going diminution of forest-cover on Java and increasing trade in the species are certain to have been detrimental (Nijman et al. 2009).

The population is estimated to number 600-900 individuals, roughly equating to 300-500 mature individuals, based on a 1:1 ratio of adults to juvenile and immature birds, as recorded in past studies (B. van Balen in litt. 2012).

It frequents primary humid forest, although individuals and even nests have been recorded in secondary forest, production forest and tropical semi-deciduous forest, preferring rugged slopes with high vegetation cover (Syartinilia and Tsuyuki 2008). While it occurs from sea-level to high mountains, it is most frequent at 500-1,000 m. Recent extensive research has estimated the average home range size of one pair to be c.400 ha (Gjershaug et al. 2004). The species's dispersal capabilities (and therefore its susceptibility to habitat fragmentation) remain poorly known, but adults appear to be highly sedentary while young birds are the main dispersers (Nijman and van Balen 2003). Juveniles and immatures are recorded in woodland and some cultivated habitats before moving to secondary and primary evergreen forest as adults (Nijman and van Balen 2003); this behaviour suggests that unsuitable habitats may not represent barriers to dispersal. It breeds every two years, principally between January and July, but can breed at any time of year (Prawiradilaga 2006); its reproductive output is generally considered to be low (Syartinilia and Tsuyuki 2008). The preferred diet consists of small mammals but it will take birds, snakes and lizards (Prawiradilaga 2006).

The key threats are habitat loss and trade. The burgeoning human population on Java brings with it intense pressure on natural resources, one aspect of which has been a massive reduction in forest cover, particularly in the lowlands. This threat continues in the form of conversion to agriculture, development and uncontrolled fire, even within protected areas. The species is also sold openly in Javan bird markets, with 30-40 reported in trade each year, and presumably many more undetected. This threat appears to be intensifying, following the elevation of the species to national bird. Individuals are taken from the wild for zoos and wildlife collections, where they tend to fare poorly (Nijman et al. 2009).

Conservation Actions UnderwayCITES Appendix II. Several surveys have targeted the species, exploring its distribution and ecology (Prawiradilaga 2006). Strict legislation protects it from hunting or trading, although this is often ineffective. It occurs in several protected areas, including Gunung Halimun, Gunung Gede-Pangrango and Meru Betiri National Parks, although these still face serious problems. An action plan has been compiled and conservation awareness programmes including several training and awareness raising workshops have been initiated (Prawiradilaga 2006, Narwatha et al. 2007). Project Garuda, which ran in 2002-2003 in Butahu, West Java, combined research with conservation activities implementing an extensive awareness raising programme including radio broadcasts, school visits and an exhibition(Narwatha et al. 2007). A nest protection programme involving local communities has been run successfully (Prawiradilaga 2006). Regular monitoring occurs in Telaga Warner Nature Reserve, Gede-Pangrango National Park and parts of G. Halimum-Salak National Park (Prawiradilaga 2006) and surveys took place around Butahu in 2002-2003 (Narwatha et al. 2007). A captive breeding programme has been underway since 1996, although as of 2006 it had failed to produce any offspring (Nijmal et al. 2009).

Conservation Actions ProposedImplement the Javan Hawk-eagle Recovery Plan. Continue ecological studies to allow appropriate management regimes to be devised. Improve management of existing protected areas, and establish further reserves, particularly in central Java, at Dieng Mountains and Gunung Slamet, and West Java in southern Cianjur district. Manage these protected areas as an established and connected network of sites, with the help of local stakeholders. Focus future population surveys on areas predicted but not confirmed to hold populations of the species (Syartinilia and Tsuyuki 2008). Continue to search for and guard nests found near human populations. Improve and enforce legislation to control trade. Continue and expand education schemes to elicit public support for the conservation of this and other threatened species on Java.

Citation:

BirdLife International 2012. Nisaetus bartelsi. The IUCN Red List of Threatened Species. Version 2014.3. <www.iucnredlist.org>. Downloaded on 03 March 2015.